We report the discovery of the transiting exoplanet NGTS-12b by the Next Generation Transit Survey (NGTS). The host star, NGTS-12, is a V=12.38 mag star with an effective temperature of Teff=5690±130 K. NGTS-12b orbits with a period of P=7.53d, making it the longest period planet discovered to date by the main NGTS survey. We verify the NGTS transit signal with data extracted from the TESS full-frame images, and combining the photometry with radial velocity measurements from HARPS and FEROS we determine NGTS-12b to have a mass of 0.208±0.022 MJ and a radius of 1.048±0.032 RJ. NGTS-12b sits on the edge of the Neptunian desert when we take the stellar properties into account, highlighting the importance of considering both the planet and star when studying the desert. The long period of NGTS-12b combined with its low density of just 0.223±0.029 g cm−3 make it an attractive target for atmospheric characterization through transmission spectroscopy with a Transmission Spectroscopy Metric of 89.4.
@article{arxiv.2009.10620,
title = {NGTS-12b: A sub-Saturn mass transiting exoplanet in a 7.53 day orbit},
author = {Edward M. Bryant and Daniel Bayliss and Louise D. Nielsen and Dimitri Veras and Jack S. Acton and David R. Anderson and David J. Armstrong and Francois Bouchy and Joshua T. Briegal and Matthew R. Burleigh and Juan Cabrera and Sarah L. Casewell and Alexander Chaushev and Benjamin F. Cooke and Szilard Csizmadia and Philipp Eigmuller and Anders Erikson and Samuel Gill and Edward Gillen and Michael R. Goad and Nolan Grieves and Maximilian N. Gunther and Beth Henderson and Aleisha Hogan and James S. Jenkins and Monika Lendl and James McCormac and Maximiliano Moyano and Didier Queloz and Heike Rauer and Liam Raynard and Alexis M. S. Smith and Rosanna H. Tilbrook and Stephane Udry and Jose I. Vines and Christopher A. Watson and Richard G. West and Peter J. Wheatley},
journal= {arXiv preprint arXiv:2009.10620},
year = {2020}
}